PREHEAT oven to 350°F if using a silver 9-inch springform pan (or to 325°F if using a dark nonstick 9-inch springform pan). Mix chocolate wafer crumbs, 2 Tbsp. of the sugar and 3 Tbsp. butter; press firmly onto bottom of pan. Bake 10 minutes.
BEAT cream cheese, 1/2 cup of the sugar and flour in large bowl with electric mixer on medium speed until well blended. Add chocolate and 2 tsp. of the vanilla; mix well. Add 3 of the eggs, 1 at a time, mixing on low speed after each addition just until blended. Pour over crust.
BAKE 45 to 50 minutes or until center is almost set. Run knife or metal spatula around rim of pan to loosen cake; cool before removing rim of pan. Refrigerate 4 hours or overnight.
MIX milk, remaining sugar, the 1/4 cup butter, remaining egg and remaining 1/2 tsp. vanilla in small saucepan; cook on medium-low heat until thickened, stirring constantly. Stir in coconut and pecans. Cool. Spread over cheesecake just before serving. Store leftover cheesecake in refrigerator.